A rapid and sensitive reverse phase high performance liquid chromatographic method is developed for simultaneous estimation of Risperidone and Trihexyphenidyl HCl in combine dose tablet. Chromatographic condition was on X bridge C18 column using phosphate buffer :Acetonitrile 0.5 ml TEA, 4.5 ± 0.5 pH adjusted by using 0.1N HCl (70:30%) as the mobile phase at a flow rate 0.8 ml/min with detection at 210nm.total run time of less then 20 min. the calibration curve were liner in the range 3 9µg/ml for Risperidone and 2-6 µg/ml for Trihexyphenidyl HCl. The method validated with respect to linearity, precision, accuracy and specificity. The mean recovery for Risperidone and Trihexyphenidyl HCl is 100.14±0.107 and 99.86±0.211, respectively. The utility of procedure is verified by application to the market formulation that was subjected tovarious stress condition. The method separated the two target drug. No chromatographic interference is observed.